Method of conditionally routing a call made to a fixed telephone number

ABSTRACT

The invention relates to a method of routing a call made by a calling party to a fixed telephone number of a called party, wherein the call is routed to one or more mobile terminals ( 34 ) via an Internet Protocol network ( 12 ) and a wireless access point ( 10 ) associated with the fixed telephone number if the one or more mobile terminals ( 34 ) are located in an area covered by the wireless access point ( 10 ), or to an alternative terminating point if the one or more mobile terminals ( 34 ) are located outside the area. A specific Service Control Point is arranged to store a list that comprises alternative terminating points for the calls to the fixed number.

TECHNICAL FIELD

The present invention relates to a method of routing a call made to afixed telephone number. In a further aspect, the present inventionrelates to a telecommunication network and a service node arranged toexecute (part of) the method.

BACKGROUND

Recently, mobile telephone services were introduced wherein a subscriberonly needs one single mobile phone that is suitable for calling via VOIPand via GSM/UMTS. If the subscriber resides at home, she may call via aradio based connection like WLAN. WIFI, Bluetooth. These radio basedconnections are collectively denoted as UMA (Unlicensed Mobile Access).GSM, UMTS and the like are denoted as GAN (Global Access Networks).Phones capable of connection in both UMA and GAN are denoted as UMA/GANphones. For a subscriber to use the phones capabilities she needs tohave either GAN and UMA subscriptions or a combined UMA/GANsubscription.

If an UMA/GAN subscriber is out of reach of an UMA area, she will callvia the GSM/UMTS network. In order to call the subscriber, a mobiletelephone number has to be dialed which is most of the time moreexpensive than dialing to a fixed number.

Most people still use their fixed telephone numbers next to their mobiletelephone. If they are called at their fixed number, they may forwardthe calls to their mobile number using a rerouting service. If they diala prefix, such as for example dialing *21, and then the mobile number,all calls to the fixed number are forwarded to the corresponding mobilephone. In this way, they will always be reached. Part of the cost forthe forwarded calls may however be billed to the called party.

SUMMARY OF THE INVENTION

A goal of the present invention is to provide a method of routing callswhich makes it possible for a called party to use a fixed telephonenumber and to receive the calls at a mobile phone, while reducing costsfor the called party as compared to the present methods.

This goal is achieved by providing a method of routing a call made by acalling party to a fixed telephone number of a called party, whereinsaid call is routed to one or more mobile terminals via an InternetProtocol network and a wireless access point associated with said fixedtelephone number if said one or more mobile terminals are located in anarea covered by said wireless access point, or to an alternativeterminating point if said one or more mobile terminals are locatedoutside said area.

The alternative terminating point may comprise an answering service oranother telephone number.

In an embodiment, if a first mobile terminal associated with said fixedtelephone number is not in said predefined area, not switched on or, hasno connection left, said call is routed to a second mobile terminalassociated with said fixed telephone number.

In another embodiment, the call is routed to every mobile terminalassociated with said fixed telephone number and present in said area.

In yet another embodiment, if said one or more mobile terminals arelocated outside said area, but said calling party is on a hot list, saidcall is routed to a mobile telephone number associated with said fixedtelephone number.

According to an embodiment, if said calling party is calling with acalling party mobile terminal, said call is routed via said IP networkonly if said calling party mobile terminal is connected via a furtherwireless access point.

Information on whether said one or more mobile terminals are locatedinside or outside said area is received from a Home Base StationController. Alternatively it may be received from a Home LocationRegister by means of subscription or Any Time Interrogation. It may aswell be received from an Secure Gateway.

In a further aspect, the invention relates to a Service node accordingto claim 11. In a further aspect, the invention relates to atelecommunication network according to claim 16.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be discussed in more detail below, using anumber of exemplary embodiments, with reference to the attacheddrawings, in which:

FIG. 1 shows a network diagram which depicts a telecommunication networkaccording to an embodiment of the invention:

FIG. 2 shows data traffic in the telecommunication network when a @homesubscriber is entering a Home Zone;

FIG. 3 shows the situation of the telecommunication network in which acheck reveals that the @home subscriber of an incoming call is locatedin the Home Zone;

FIG. 4 shows the situation of the telecommunication network when thesubscriber is leaving the Home Zone;

FIG. 5 shows an example of the telecommunication network in thesituation in which the subscriber is not in the Home Zone;

FIG. 6 shows an example of a telecommunication network handling a callto a fixed number that belongs to broadband subscriber.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

The basic idea of the present invention is to provide subscribers with afixed telephone number the facility to route calls that are made to thefixed telephone number either to a mobile phone of the subscribers whenthey are located in a so-called ‘Home Zone’, or else to an alternativeterminating point, such as a voice mail of the subscriber that mayreside in the telecommunication network of a telecom provider. The HomeZone, according to an embodiment, is determined by an area which iscovered by one or more wireless access points. The service which isprovided to the subscribers is referred to as the ‘@home’ service. Themethod according to the invention will give an @home-subscriber and acalling party a fixed line kind of experience.

In FIG. 1, a network diagram is shown which depicts a telecommunicationnetwork according to an embodiment of the invention. Thetelecommunication network comprises a wireless access point 10, such asa WiFi enabled modem installed at the subscriber premises, an InternetProtocol (IP) network 12, a Security Gateway (SeGW) 14, a Home BaseStation Controller (HBSC) 16, a Mobile telephone network 18, and a fixedtelephone network 20. Furthermore, the telecommunication networkcomprises a Telephony switch 22, Service Control Point (SCP) 24, a MediaGateWay (MGW) 26. The telecommunication network also comprises a BaseStation Controller (BSC) 28 and a Base Transmission Service (BTS) 30.

In this embodiment, a Service Switching Point (SSP) 21 is arranged inthe Telephony switch 22. A database, not shown, is arranged forcomprising information needed by the SCP 24 for routing purposes. Thedatabase may be arranged in the SCP 24, as a separate database like aService Data Point (SDP), or arranged in another node in the network.

In FIG. 1, a mobile terminal 34 is depicted which is arranged tocommunicate both via said wireless access point 10 and said BTS 30. Anexample of such a mobile phone 34 is a UMA/GAN capable handset which ispresently available on the market.

The Security Gateway 14 is arranged to setup a secure tunnel through theIP network 12 via the assess point 10 to the mobile terminal 34. In FIG.1, the SeGW 14 and the MGW 26 are depicted as separate nodes, but theymay as well be combined in one node.

The HBSC 16 is arranged to register alternative access possibilities ofUMA/GAN subscribers. The HBSC 16 communicates with the Mobile telephonenetwork 18 using the Mobile Application Protocol, and at the other endit communicates with the SeGW 14. The Mobile telephone network 18 isarranged for providing telecommunication services for GSM subscribers.The Telephony switch 22 is arranged to switch Time Division Multiplexing(TDM) traffic. It should be noted that in FIG. 1 the telephony switch 22is depicted separate from the fixed telephone network 20, while in factit can be seen is being part of the fixed telephone network. The SCP 24is an IN node that executes IN services. This IN node provides thesubscribers to be called to their fixed telephone number while receivingthe calls on a mobile phone according to the method described below. TheSSP 21 in the Telephony switch 22 triggers the SCP 24 whenever aconnection needs to be set up to the fixed number. To set up aconnection, at the signalling level, a phone number is transmitted viathe network. There are three basic ways the SSP 21 can select whichcalled numbers to forward to the SCP. First is known as “all B or allquery” In this case the SSP 21 will forward every called number to theSCP 24. Alternatively the SSP 21 comprises a list of phone numbers forwhich the SSP 21 does not directly connect the call to the destination,but first accesses the SCP 24 to check whether the final destination iscorrect. Instead of the called number also the range in which the callednumber is or the subscription class of the called number may be used. Iffor example, a called party has forwarded all the calls to anothernumber, the SSP 21 will ask the SCP 24 for every call to which numberthe call needs to be connected.

The SSP 21 will receive the correct number from the SCP 24 and willestablish a connection to the correct number. Please note that the term‘number’ is not necessary the same as telephone number. A voice mail boxassociated with a telephone number will have in the network a different‘number’ than the telephone.

The SSP 21 will receive the request for setting up a connection from thenetwork, and then the SSP 21 gives the request as a “Initial DP” messageto the SCP 24.

The Telephony switch 22 communicates with the MGW 26, the fixedtelephone network 20, and with the Mobile telephone network 18 using theISDN User Part for controlling the routing of the call and TDM for theactual voice path. The SSP 21 in the Telephony switch 22 communicateswith the SCP 24 using the INAP (Inteligent Network Application Part)protocol. The MGW 26 is arranged to convert VoIP traffic received fromthe IP network 12 to TDM traffic for the Telephony switch 22. The MGW 26communicates with the IP network 12 using the well known SessionInitiation Protocol. The BSC 28 communicates to the Mobile telephonenetwork 18 (i.e. a Mobile Switching centre in said Mobile telephonenetwork 18) using the so-called Base Station System Application Part(BSSAP) protocol. The SeGW 14 communicates with the IP network using IP.It is noted that other protocols may be used as will be clear to theskilled person.

Now different call flows will be discussed with reference to FIGS. 2-5.It is noted that the description of FIGS. 2-5 are exemplary, and thatother embodiments are possible. Calls to a fixed telephone number of thesubscriber will be routed by the provider of the fixed telephone network20 to the Telephony switch 22. All incoming calls for the fixed numberconcerned on the Telephony switch 22 will trigger IN (via IN all queryor comparable mechanism). The SCP 24 will execute a first check byquerying the database like an SDP, to see if there is a relation betweenthe fixed telephone number and a Mobile Subscriber Integrate ServiceDigital Network number (MSISDN)). The SCP 24 receives the CalleD PartyNumber (CDPN) from the Telephony switch 22 in an InitialDP message.Based on this CDPN the first check is made. In case an MSISDN does existfor the CDPN, the SCP 24 executes a second check to test if this @homesubscriber is located in the Home Zone or not. The SCP 24 is arranged toreceive information on whether the @home subscriber is located in oroutside the Home Zone from a so-called area presence service.

In an embodiment, this information is received from the SeGW 14. TheSeGW 14 is arranged to indicate by means of a push action if and when asubscriber registers and de-registers on the SeGW 14. In an embodiment,the Syslog protocol is used for that and this protocol allows the SeGW14 to send event notification messages across the IP connection betweenthe SeGW 14 and the SCP 24 or other possible Event MessageCollectors—also known as Syslog Servers. The SeGW 14 is arranged to sendcertain event notification messages (for example UMA in and UMA out) toa specific Syslog server, such as the SCP 24. In an embodiment, a Javaapplication may be loaded on an additional server, in which theapplication receives the event notification messages and convert thereceived messages (indicating registering and deregistering) and messageinformation (IMSI value) to Lightweight Directory Access Protocol (LDAP)so that a Home Zone indicator in the database can be updated for acertain subscriber. The additional server may be for example a SUNserver located between the SCP 24 and the SeGW 14, not shown in FIG. 1.It should be noted that the Java application may instead be loaded onthe SCP 24 or on the SeGW 14.

In another embodiment, the SCP 24 receives information about thelocation (in or out the Home Zone) from the HBSC 16. In this case, theSCP 24 will receive update messages from the HBSC 16 that give thenecessary information. The mobile terminal 34 is then registered as outthe Home Zone, when there is no connection.

In an other embodiment the SCP 24 receives the entry or exit updates forthe Home zone by means of subscription or ATI (any time interrogation)from a Home Location Register (HLR) not shown.

FIG. 2 shows data traffic in the telecommunication network when the@home subscriber is entering the Home Zone, see arrow 40 which indicatesa movement of the mobile terminal 34 into a Home Zone. It can be seenthat the mobile terminal 34 on entering the Home Zone registers on theSeGW 14, see arrow 42, and that the SCP 24 is informed about this event,see arrow 44. The message sent to the SCP 24 will indicate registrationor de-registration.

Therefore a link is made in the SCP 24 between the fixed telephonenumber and the MSISDN or IMSI to be able to store whether the @homesubscriber is located in the Home Zone or not.

In the situation in which the second check reveals that the @homesubscriber of an incoming call, see arrows 51 in FIG. 3, is located inthe Home Zone, the SCP 24 will instruct the Telephony switch 22 via theSSP 21 to route the incoming call to the mgw 26, see arrow 54. I.e. theSCP 24 will send a Connect message to the SSP 21 in the Telephony switch22, see arrow 53, with the MSISDN of the @home subscriber. This MSISDNwill be then used as the CDPN. The CallinG Party Number (CGPN) will notbe touched. The telephony switch 22 of the called party will route thecall to the MGW 26 (controlled by the SSP 21 in the Telephony switch 22)which in turn will route to the mobile terminal 34 through the IPsectunnel, see arrow 56, from the SeGW 14 to the mobile terminal 34. In theabove described scenario, the subscriber resided in the Home Zone. InFIG. 4, the subscriber is leaving the Home Zone, see arrow 60. It can beseen that the mobile terminal 34 in that case deregisters from the SeGW14 and that the SCP 24 is informed about this event, see arrows 62, 64.Arrow 62 is in this case the breaking of the IPsec tunnel in thesituations ‘no connection left’ or ‘mobile switched of’. The SeGW 14will report this by means of an UMA out message to the HBSC 16 and inthis embodiment also to the SCP 24 via the Java application.

In the following table, an example is given of the list that is storedon or by the SCP 24. The list comprises for all subscribers to the @homeservice, a fixed telephone number, such as “B1fixed”, one or moreassociated areas, such as “area1”. “area2”, and the associatedalternative terminating points, such as “C1 alternative endpoint”. Anarea presence indicator “area in/out” is stored and updated for allexcept one alternative terminating points. In the example shown below, acall to the fixed telephone number “B1fixed” will be routed to “Cnalternative endpoint” when the mobile terminal of the subscriber (andthus the subscriber herself) is in none of the defined areas. An exampleof such an area is a coverage area of one or more WLANs.

B1fixed area1 area2 C1 alternative endpoint area in/out C2 alternativeendpoint area in/out C3 alternative endpoint “in” B2fixed area3 C5alternative endpoint area in/out C6 alternative endpoint area in/out C7alternative endpoint “in”

In the example of the list above, it can be seen that the subscriber of“B2fixed” has only one area which defines the Home Zone. The alternativeterminating point “C7 alternative endpoint” may for example be a voicemail, or another alternative number, which is reached if the subscriberis not in “area3”.

FIG. 5 shows an example of the telecommunication network in thesituation in which the subscriber is not in the Home Zone. In this case,the second check will reveal that the subscriber is no longer located inthe Home Zone. In this case the SCP 24 will instruct the SSP 21 in theTelephony switch 22 to route the incoming call, see arrow 71 and 72, toalternative termination point by means of a “connect” message. Thealternative terminating point can be a voicemail of the mobile terminal34, implemented on voice mail platform 32 of the subscriber that may belocated in the mobile network of the provider. The alternativeterminating point may also be a number of an answering service, thevoice mail of the fixed number. Each of these possible alternativeterminating points are uniquely identified by a CDPN. The SCP 24 willsend a Connect message to the Telephony switch 22, see arrow 73, withthe telephone number of the voice mail platform 32 in Mobile telephonenetwork 18. This telephone number will be used as the CDPN. As the voicemail platform 32 needs to know to which voice mail the call needs to bedirected to according to an embodiment, the Redirecting Number (RN) isset to the MSISDN number of the subscriber. This means that the CGPNwill not be touched. Note that it is assumed that the voicemail platform32 makes use of an RN to be able to determine the correct voicemail fora particular subscriber. Alternative to RN is super imposed digits tointernal network numbers. Internal numbers have than more digits thenthe actual mobile or fixed number. Arrow 74 indicates the connection tothe mobile telephone network 18.

According to an embodiment, on the additional server a Java applicationis loaded in order to support the @home service described above. Theadditional server may be a SUN server located between the SCP 24 and theSeGW 14. The Java application is arranged so as to give the additionalserver the ability to:

-   -   receive Syslog messages;    -   filter on MessageIDs in Syslog messages—convert a combination of        MessageID and information in the Syslog message (IMSI) to LDAP        to be able to change the setting of the Home Zone indicator for        a certain subscriber in the database that is used by the IN        service.

According to an embodiment, the SCP 24 is arranged to store thedatabase. In the database, the relation between fixed telephone number,MSISDN/IMSI and Home Zone Indicator (In/Out) is stored. Furthermore, theSCP 24 is arranged to provide the possibility for a link between thefixed number, the MSISDN/IMSI to be changed remotely. This is forexample applicable when a mobile number changes. The SCP 24 hastherefore a link to a Customer Business Support System (BSS) not shown.

The following information has to be provisioned for a subscriber: fixedtelephone number, MSISDN. IMSI. Provisioning of this information may bedone by means of Customer Administration Interface (CAI) scripts andLDAP.

In an embodiment, the Home Zone indicator is set to ‘out’ by default toindicate that the subscriber is outside the Home Zone.

It is noted that next to calls to the subscribers of a ‘@Rome’ service,also calls to VoIP subscribers of may be routed to the Telephony switch22. In this case, a distinction must be made between the two trafficstreams. This may also be done by the SCP 24. For example, if therelation between fixed number and MSISDN does not exist then the SCP 24may assume that the call is destined to a subscriber with a regularfixed number without the @home service.

The SCP 24 will send a Continue message to the Telephony switch 22, seearrow 76, indicating to route the call on to the regular fixed number,see arrows 77, 78, 79. This call will then be terminated by for examplea broadband modem 80 and a phone 82 in communication with said modem 80,see FIG. 6.

It should be appreciated that the method described above can also beused for routing calls made to a fixed number belonging to employees ofa certain company. Instead of the @home service, a service provided tocompanies may be called @office. In an office, a plurality access pointmay be present. A call to a fixed number of an employee of the companywill then be routed to a mobile terminal of the employee, if theemployee is within reach of one of the access points in the office. Ifthe employee is out of the office. i.e. out of reach of the plurality ofaccess points, the call will be routed to an alternative terminatingpoint.

In an embodiment of the invention, the alternative terminating pointcomprises an answering service. The answering service may be the voicemail platform 32 shown in FIG. 5, or a call back service. It may also bean answering system that only plays an announcement for the callingparty. By routing the calls to the answering service, the called partywill not be billed for any forwarded call to his mobile. e.g. mobiletelephone.

According to another embodiment, the alternative terminating pointcomprises another (i.e. a different) telephone number. This may be afixed, a fixed IP number or a mobile number, such as a further mobileterminal in communication with said Internet Protocol network 12. Inthis case the further mobile terminal is also arranged to receive callsvia WiFi/WLAN. This mobile terminal may be a mobile phone of anattendant or colleague of the subscriber.

In an embodiment, the SCP 24 is arranged to store a so-called ‘huntinglist’ for each fixed telephone number for which the service is provided.If a first mobile terminal associated with the fixed telephone number isnot in the predefined area or not switched on, the call is routed to asecond mobile terminal associated with said fixed telephone number. Thehunting list may be defined by the subscriber. The subscriber may forexample get access to a website of the provider in order to enter thehunting list. The hunting list comprises the MSISDN numbers of themobile phones of the persons entered by the subscriber. If none of thesepersons (i.e. their mobile phones) are in the predefined area, the callwill be routed to the alternative terminating point, such as theanswering service.

In another embodiment, the call is routed to every mobile terminalassociated with the fixed telephone number and present in the Home Zone.This means that the call will result in a parallel ringing of the mobilephones present in the Home Zone. The call will be connect to the mobilephone of the person that first picks up the phone.

According to yet another embodiment, the call is routed to a mobiletelephone number associated with the fixed telephone number if themobile terminal 34 is located outside the Home Zone, but the callingparty is on a so-called ‘hot list’. In this case, the call is forwardedvia e.g. a GSM/UMTS network if the calling party number is on the hotlist. The subscriber may for example put her husband or her mother onthe hot list so that these persons will not be connected to an answeringservice.

According to a special embodiment, it is checked if the calling party isconnected to a wireless access point. If the calling party is callingwith a mobile terminal to the fixed telephone number, the call is routedvia the IP network 12 only if the mobile terminal of the calling partyis connected via a wireless access point. In this embodiment, the SCP 24receives in the INAP initial DP message both the calling party number(CGPN) as well as the called party number (CDPN). The SCP 24 will thencheck whether the calling party is in or out his Home Zone according toa method similar to the one described above for the check for the calledparty.

The present invention has been explained above with reference to anumber of exemplary embodiments. As will be apparent to the personskilled in the art, various modifications and amendments can be madewithout departing from the scope of the present invention, as defined inthe appended claims.

The invention claimed is:
 1. A method, in a telecommunication network,of routing a call made by a calling party to a fixed telephone number ofa called party, the method comprising: routing said call to a telephonyswitch of a telecommunication network, wherein said call triggersIntelligent Network (IN) functions; a service control point (SCP) of thetelecommunication network, based on the fixed telephone number receivedin a CalleD Party Number (CDPN) from the telephony switch, executing afirst check by querying a database for determining a relationshipbetween the fixed telephone number and one or more mobile terminalsassociated with the CDPN; the SCP executing a second check to determineif at least one of said one or more mobile terminals is registered on aSecurity Gateway of the telecommunication network, if the at least oneof said one or more mobile terminals is determined to be registered onthe Security Gateway, routing said call to the at least one of said oneor more mobile terminals via a wireless access point of an InternetProtocol (IP) network and through a secure tunnel set up by the SecurityGateway through the IP network, or routing the call to an alternativeterminating point if said one or more mobile terminals are determined tonot be registered on the Security Gateway.
 2. The method according toclaim 1, wherein said alternative terminating point comprises ananswering service.
 3. The method according to claim 1, wherein saidalternative terminating point comprises another telephone number.
 4. Themethod according to claim 1, wherein if a first mobile terminalassociated with said fixed telephone number is not registered on theSecurity Gateway, said call is routed to a second mobile terminalassociated with said fixed telephone number.
 5. The method according toclaim 1, wherein said call is routed to every mobile terminal associatedwith said fixed telephone number and registered on the Security Gateway.6. The method according to claim 1, wherein if said one or more mobileterminals are not registered on the Security Gateway, but said callingparty is on a hot list, said call is routed to a mobile telephone numberassociated with said fixed telephone number.
 7. The method according toclaim 1, wherein if said calling party is calling with a calling partymobile terminal, said call is routed via said wireless access point ofsaid IP network only if said calling party mobile terminal is connectedvia a further wireless access point.
 8. The method according to claim 1,wherein information on whether said one or more mobile terminals areregistered on the Security Gateway is received from the SecurityGateway.
 9. The method of claim 1, further comprising updating areapresence indicators in an IN service database in the SCP based onentry/exit triggers received from the Security Gateway so that when anentry trigger is received, the area presence indicator is given a value‘in’ and when an exit trigger is received, the area presence indicatoris given a value ‘out’.
 10. The method of claim 9, wherein theentry/exit triggers are syslog messages and are transformed intoLightweight Directory Access Protocol (LPAD) messages to be sent to theIN service database, wherein the LPAD messages are used to update thearea presence indicators in the IN service database.
 11. A Service nodefor use in a telecommunication network, said Service node being arrangedto receive a routing request from a Service Switching Point of a fixedtelephone network and to send a routing order to said Service SwitchingPoint, said Service node being arranged to: store for each of aplurality of subscribers: a fixed number, one or more related areasassociated with said fixed telephone number, and a list comprising oneor more associated alternative terminating points and for eachalternative terminating point an area presence indicator; receiveentry/exit triggers from a Security Gateway, each entry/exit triggercorresponding to one of the alternative terminating points andindicating registration/deregistration of the corresponding alternativeterminating point on the Security Gateway; update said area presenceindicators based on the received entry/exit triggers so that when anentry trigger is received, a corresponding one of the area presenceindicators is given a value ‘in’ and when an exit trigger is received,the corresponding area presence indicator is given a value ‘out’;determine said routing order by finding, in the list comprising one ormore associated alternative terminating points for a subscriberindicated in the received routing request, an alternative terminatingpoint in said list for which the corresponding area presence indicatorhas a value ‘in’; and send the routing order to said Service SwitchingPoint.
 12. The Service node according to claim 11, wherein said Servicenode comprises a database arranged to store said list.
 13. The Servicenode according to claim 11, wherein said alternative terminating pointsassociated with one fixed telephone number are sorted in a predefinedorder of priority.
 14. The Service node according to claim 11, whereinsaid list has at least one alternative endpoint with an area in/outindication with a fixed “in” value.
 15. The Service node according toclaim 11, wherein said Service node comprises a Service Control Point.16. A telecommunication network comprising: a fixed telephone networkwith a Telephony switch that includes a Service Switching Point; aService node for determining whether a mobile terminal is located in oroutside a Home Zone; a Security Gateway in communication with theService node, the Service node determining whether the mobile terminalis located in or outside the Home Zone based on whether the mobileterminal is registered on the Security Gateway; an IP network incommunication with said telephony switch and said Security Gateway; andone or more wireless access points in communication with said IPnetwork, said wireless access points being arranged to connect telephonecalls received from said IP network to the mobile terminal through asecure tunnel set up by the Security Gateway in an unlicensed mobileaccess network, wherein the Service node routes the telephone calls tobe connected by the wireless access points if the Service nodedetermines that the mobile terminal is located in the Home Zone.
 17. Thetelecommunication network according to claim 16, further comprising amedia gateway, wherein said mobile terminal is connected via saidSecurity Gateway and said media gateway to the Telephony switch.
 18. Amethod for providing presence information of a mobile terminal in acoverage area having one or more wireless access points, the methodcomprising: a Security Gateway setting up a secure tunnel towards saidmobile terminal; the Security Gateway providing entry/exit triggersidentifying registration and deregistration of said mobile terminal onthe Security Gateway as syslog events to a syslog server; and saidsyslog server providing said presence information.